Matthew Knott and Lisa Cox

Queensland Liberal MPs have lashed out at former minister Ian Macfarlane for defecting to the Nationals, accusing him of disloyalty and selfishness comparable to that of disgraced former Speaker Peter Slipper.

Ian Macfarlane confirms defection to Nationals

Mr Macfarlane's shock defection on Thursday ensured a rocky end for the parliamentary year for Prime Minister Malcolm Turnbull, who was already under pressure to sack Special Minister of State Mal Brough for his role in the James Ashby affair.

The switch has also exposed longstanding tensions within the Queensland Liberal National Party, a new party formed by the merger of the state Liberal and National parties in 2008.

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"In politics, we are all ambitious people – 95 per cent of us think we should be on the front bench. But what 99.94 per cent of us don't do is game the system like Peter Slipper, switching to the crossbench to gain the Speakership.

Former ministers Warren Truss and Ian Macfarlane are among 16 retiring MPs who will benefit from a generous six-figure parliamentary pension. Photo: Andrew Meares

Fellow Queensland Liberal MP Warren Entsch said: "It is a disappointing decision given how long he has been in the Liberal Party.

"It's a decision he has to live with."

Mr Entsch said that if Mr Macfarlane had wanted to change parties he should have done so at the next election so his constituents could give their approval.

"I don't think he's doing it for the benefit of his own constituents – he's doing it for his own personal interests."

Mr Macfarlane, who has held the regional Queensland seat of Groom since 1998, declined to comment on Friday.

The former industry minister was dumped from the frontbench in Mr Turnbull's reshuffle to make way for younger talent.

"It's a decision I've arrived at on the basis that I'm keen to ensure that regional Queensland and regional Australia continue to be well-represented," he said on Thursday.

"I could have gone either way when I first went into Groom, I had discussions with both parties ... I'm as National Party as anyone," mentioning his "five Akubras and seven pairs of R.M. Williams".

All Queensland federal Coalition MPs belong to the Liberal National Party but align themselves in Canberra with either the Liberals or the Nationals. The Nationals plan to push for another frontbench position following Mr Macfarlane's decision and possible future defections by several Liberals.

In an interview with ABC radio in Toowoomba on Friday, Mr Macfarlane said he would be keen to return to cabinet.

"In terms of what I have to offer and my passion which is still to represent the people of Toowoomba and regional Queensland, you do that best if you're in the ministry, you do it even better if you're in cabinet," he said.

"In any cabinet you not only need age and experience but you also need people who live west of the Great Dividing Range."

Industry Minister Christopher Pyne said on Friday he was "disappointed" by the defection and believed Mr Macfarlane had had a "pretty good run in cabinet" since his appointment in 2001.